Originally Posted by ruckzac

I think that the flight has to be KE-marketed for this to work. So, if KE doesn't codeshare the desired route, this wouldn't work. You could hypothetically ask KE to sell you a DL-marketed flight on KE stock, but I think this would fall under the normal accrual rules.

Besides, this is likely changing soon due Delta and Korean Air's expanded partnership announced in March.